Characterization of half-metallic L21-phase Co2FeSi full-Heusler alloy thin films formed by rapid thermal annealing

Abstract

The authors developed a preparation technique of Co 2 FeSi full-Heusler alloy films with the L2 1 -ordered structure on silicon-on-insulator (SOI) substrates, employing rapid thermal annealing (RTA). The Co 2 FeSi full-Heusler alloy films were successfully formed by RTA-induced silicidation reaction between an ultrathin SOI (001) layer and Fe/Co layers deposited on it. The highly (110)-oriented L2 1 -phase polycrystalline full-Heusler alloy films were obtained at the RTA temperature of 700 ºC. Crystallographic and magnetic properties of the RTA-formed full-Heusler alloy films were qualitatively the same as those of bulk full-Heusler alloy.This technique is compatible with metal source/drain formation process in advanced CMOS technology and would be applicable to the fabrication of the half-metallic source/drain of MOSFET type of spin transistors.

Highly ordered Co2FeSi Heusler alloys grown on Ge(111) by low-temperature molecular beam epitaxy

“…14 There are many spintronic studies of this material. [15][16][17] Using LTMBE techniques, we demonstrate high-quality epitaxial growth of Co 2 FeSi͑111͒ films on Ge͑111͒. We find that the epitaxial Co 2 FeSi layers have an L2 1 -ordered crystal structure, where the interface between Co 2 FeSi and Ge is atomically flat.…”

On the half-metallicity of Co2FeSi Heusler alloy: Point-contact Andreev reflection spectroscopy andab initiostudy

“…Even though Co 2 FeSi alloy appears to be half-metallic only theoretically and only under stringent conditions on U ef f , it has been extensively referenced in the literature as such. [17][18][19][20][21][22] This prediction, however, is at odds with several experimental measurements based on Point Contact Andreev Reflection (PCAR) spectroscopy 17,22,23 , which yield values of P ∼50%, far lower than 100%. The goal of this Rapid Communication is to reconcile the results of computational predictions with experimental measurements for Co 2 FeSi.…”

Devices and Applications: Spin Transistors and Spin Logic Devices

“…Full-Heusler alloys containing Si, such as CFS, CFSA, and CMS, can be considered to be a kind of silicide, and thus they could possibly be formed by RTA-induced silicidation. Takamura et al proposed an RTA technique for full-Heusler alloy thin films using a silicon-on-insulator (SOI) substrate [42,43], in which CFS thin films were formed by RTA-induced silicidation of an Fe/Co/SOI multilayer, as shown in Fig. 4a.…”